Quick link load tests and bad links

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Messages 1 - 20 of total 21 in this topic << First  |  < Previous  |  Show All  |  Next >  |  Last >>
Banquo

climber
Amerricka
Topic Author's Original Post - Mar 29, 2012 - 02:09pm PT
I bought some inexpensive stainless steel 5/16" quick links to attach anchor chains. They came with tags that proclaimed a working load of 1570 lbs and Chinese manufacture. When they arrived, it was obvious to me that the threads didn't engage properly so I tested 3 of them. I tested two that appeared to be the worst of the lot and one that appeared to be the best. The strongest broke at 2700 lbs and the weakest at 1500 lbs (6.7 Kn - roughly open carabiner strength). All three pulled apart at the threads with little or no thread damage. I sent all of them, including the tested ones, back to the supplier and he refunded the price and my shipping costs. Somehow I didn't take photos of these but they just opened up at the gate.

Cragnshag gave me two 5/16" SS links to test for comparison. One marked Thailand broke at 14,600 lbs and one sourced from McMaster-Carr took 15,700 lbs (70 kN) without coming apart but I quit because my test jig broke. Both of these were tested on a 1/2" bolt. The threads still function on both. Testing on a smaller diameter bolt would probably result in lower breaking loads since the failure occurs where the link rounds the bolt.

Safety factors for quick links vary between 3 and 10 depending on application and supplier. I believe that the OSHA standard is a factor of 3 for lifting and 5 for personnel but I am not sure about this.

Quick link quality varies a great deal. Sometimes this can be detected visually but it may require testing to be sure. I think they are hard to make and the way to make fabrication easier is to be sloppy with the threads. I would suspect that they have to roll the threads before bending the link making it hard to line up the threads. If the threads fit loose, they are easier to line up.

It might be possible for the threads to feel tight even though they are not if the two ends don't line up perfectly.

Never clip into the links or chains for anything other than rappelling.

Even with the threads open, these links require about 800 lbs to bend open.

The third link in the photo is a a 1/4" carbon steel one for comparison.

Be careful out there.

Quick link tests
Quick link tests
Credit: Banquo
locker

Social climber
CO
Mar 29, 2012 - 02:32pm PT


Great!!!...

One more thing to worry about...



But THANKS a hell of a LOT for posting this...

Interesting...

I've often wondered about them considering how many we use on a very regular basis...
nutjob

Gym climber
Berkeley, CA
Mar 29, 2012 - 03:29pm PT
Thank you very much for some useful data to inform our judgment!

I get a little freaked seeing how small of a quicklink dealie my lady has on her harness for emergency/bail situations (smaller diameter metal than that)... I say to her "would you rap off of one of those?" and she says "sure." She's still here.

Cuckawalla

Trad climber
Grand Junction, CO
Mar 29, 2012 - 05:11pm PT
Thanks for the useful info! Something I would be interested in seeing is the strength of Lap-links. These are comonly used around here. Typically people will use a section of chain and connect it to the hanger by a laplink. Most are 3/8". If they are strong, it is a nice cheap way of going about things!

Thanks,
Jesse Zacher
cragnshag

Social climber
san joser
Mar 29, 2012 - 08:53pm PT
This lot of defective quick links is still for sale on Ebay. At least the seller revised the strength of the quick links in the description to say "break load - 1,500 lbs" based on Dan's results and returned purchase. But he didn't drop the price. Go figure!


Here is the text of the Ebay auction:

YOU ARE BUYING 10 NEW

MIBRO

STAINLESS STEEL 5/16" QUICK LINKS

BREAK LOAD - 1,500 LBS.

LINK DIMENSIONS CORRESPOND WITH PICTURE

OVERALL LENGTH - 2.844"
INSIDE WIDTH "C" - 3/4"
INSIDE LENGTH "B" - 2.222 "
WIRE GAUGE "A" - 0.311 "
OPENING WIDTH "D" - 0.370 "

DON'T BE CAUGHT PAYING $6+ EACH ELSEWHERE!


ALL 10 QUICK LINKS FOR ONE MONEY!!!

5 STAR & FEEDBACK POLICY:
WE PRIDE OURSELVES ON CUSTOMER SATISFACTION. IF YOU HAVE ANY QUESTIONS BEFORE OR AFTER RECEIVING YOUR ITEM PLEASE CONTACT US! WE FEEL THAT A GOOD TRANSACTION IS NOT DONE UNTIL THE BUYER IS COMPLETELY HAPPY, THEREFORE WE DO NOT LEAVE FEEDBACK UNTIL WE HAVE RECEIVED IT. DUE TO THE NEW DSR STAR RATINGS AND CHANGE IN FEEDBACK FOR SELLERS IF YOU ARE UNSATISFIED WITH YOUR PURCHASE FOR ANY REASON FEEL FREE TO CONTACT US BEFORE LEAVING A NEGATIVE OR NON 5 STAR RATING.



Let's see here:

$2.80 buys you a 1,500 lb SS quicklink = 536 lbs per dollar.
$6.00 buys you a 14,000 lb SS quicklink = 2,333 lbs per dollar.

Perhaps these bad links could be used for dog leashes or something!



SteveW

Trad climber
The state of confusion
Mar 29, 2012 - 10:35pm PT

I'm certainly gonna look hard at that next anchor with a quick link on
it. Thanks, Banquo!!!!
David Plotnikoff

Mountain climber
Emerald Hills, CA
Mar 29, 2012 - 11:52pm PT
I buy these by the fistful at Lowe's in the bay area and at the lumberyard in Mammoth so that my kid can bail off sketchy stuff and not sweat getting dad all upset about sacrificing another biner.

I think the reason we're so complacent is they're never absorbing the Kn of a lead fall, just the weight of lowering a 50lb girl off a bolt or anchor.

Never seen True Value Hardware mark the actual provenance of these guys. Not that "made in China" would automatically be a bad thing. $3 for a quicklink vs. $7 for a biner. We'll go with the quicklink.
TrundleBum

Trad climber
Las Vegas
Mar 30, 2012 - 12:18am PT
Never clip into the links or chains for anything other than rappelling.

It's that simple, I have no worries rap'n from dbl 1500 lb screw links...

'N I get pissy when noob's get pissy with me for demanding that belay anchoring is done by lifting all hardware and using a biner straight to the hangers.
TrundleBum

Trad climber
Las Vegas
Mar 30, 2012 - 12:20am PT
Chinese hardware is simply a 'no can do' in industrial and entertainment rigging.
mucci

Trad climber
The pitch of Bagalaar above you
Mar 30, 2012 - 12:25am PT
'N I get pissy when noob's get pissy with me for demanding that belay anchoring is done by lifting all hardware and using a biner straight to the hangers.

I demand that as well.

Good practice.

Banqs- I am ready to break some stuff.
Ratagonia

Social climber
Mt Carmel, Utah
Apr 12, 2012 - 01:49pm PT
"Safety factors for quick links vary between 3 and 10 depending on application and supplier. I believe that the OSHA standard is a factor of 3 for lifting and 5 for personnel but I am not sure about this."

SWL and WLL are rating systems that imply a mean breaking strength (what wee climbers are used to) of 5X the SWL rating. OSHA may require MORE for life safety applications, but nobody would go below 5X, even for just lifting crap, because even lifting crap you don't want it to break.

So when you break a link with an SWL of 1500 lbs, and it breaks at 1500 lbs, you can know one very important thing - these things are total crap. It tells you very little about when the next one will break - could be 6000 lbs, could be 50 lbs. What you do know is that it is very, VERY far out of specification, and therefore you do not want to have anything to do with it. Ornamental at best.

I think you do better to buy smaller, lower-rated rapides from a reputable manufacturer, built to a standard than buy bigger pieces of crap and add lots of prayer.

I used to buy rapides at my local (SLC) Bolt and Nut Supply and figured they were a good place, they would buy reputable stuff. Then got one batch that was total crap. So I am on the French Maillons Rapides bandwagon since. Yes, it is more trouble than stopping by Lowe's on your way to the crag, but...

http://canyoneeringusa.com/shop/product.php?productid=16285&cat=252&page=1

Tom
Ojai Alex

Trad climber
Ojai, CA
Oct 31, 2017 - 03:29pm PT
All three pulled apart at the threads with little or no thread damage.

Very interesting. A friend of mine set up a zip line with cheap quicklinks in the system. After some fat people jumped all over the thing one of the quicklinks basically failed. They werenít familiar with vectors and figured it was good.

The link was bent open like you describe. It looked like they forgot to screw the gate closed, which is what I thought happened. But now I think it pulled open at the threads. Scary.
healyje

Trad climber
Portland, Oregon
Oct 31, 2017 - 03:36pm PT
CE-rated, stainless quicklinks are certainly available from reputable outlets, but they cost more.
Spider Savage

Mountain climber
The shaggy fringe of Los Angeles
Nov 1, 2017 - 03:11pm PT
Valuable info bump.

It seems obvious to me that quicklinks are only for rappelling.

When I set new routes at Texas Canyon I put two quicklinks on each of the two hangers at rap stations to facilitate pulling a rope through links perpendicular to the rock face.

Apparently many people were offended by this and there was judgements flying all about. The7 disappeared with in a few years. (Also some hangers too.)

Two links on a bolt hanger seemed so logical as to use but I guess some people don't get it.
Ojai Alex

Trad climber
Ojai, CA
Nov 1, 2017 - 03:18pm PT
^^^ Iíve used that setup (two links on each hanger) on dozens of pitches. What did people not like about that at Texas Cyn?
tradmanclimbs

Ice climber
Pomfert VT
Nov 1, 2017 - 04:00pm PT
Totally irrelevant post. Your bad link broke at over 4,000 lbs.
1. I would never use 1/4" for anything. I won't even use wave bolts for the simple reason that they don't have enough meat. Wave bolts are stronger than most things out there but only if undammaged. More meat = able to withstand more dammage and still be strong enough.
2. 5/16th" quick links are totally Truck. I did my own tests and I can break Dynamic climbing rope all day long with 5/16th" quick links. you supply the Dynamic climbing rope and I will break it for you. $100 bucks a pop. If the link fails you keep the $100. your rope breaks I keep the $100. :)

3. If you are dumb enough to trust you life to a link that is not screwed shut... Oh well.....

4. the only thing that counts is the weakest link in the system. Obviously you do not want that link to be the anchor. If the anchor is stronger than climbing rope then any discussion about makeing it even stronger than climbing rope is of limited value INMOP

tradmanclimbs

Ice climber
Pomfert VT
Nov 1, 2017 - 04:28pm PT
OK i see you did not have photos of the really bad tests. To be fair the quick links that I use and the ones I tested were bought from Climb tech but they are china manufacturer. however I have also broken climbing rope with a 1/4" quick link that I found. the climbing rope always breaks at the knott
tradmanclimbs

Ice climber
Pomfert VT
Nov 4, 2017 - 03:52pm PT
Just broke a 2in tow strap twice with the 5/16th quick link that lives on the back bumper of my dump truck. same one that has broken a bunch of climbing ropes
Rankin

Social climber
Winston-Salem, North Carolina
Nov 4, 2017 - 06:11pm PT
Unless 6.7 kN is not the lower end of failure of these quick links then I take this as good news. If 5/16" from a questionable Chinese manufacturer is failing at 1500 lbs then the only issue is on a fixed draw or if someone clips the quick link on a new pitch or extension rather than the hanger. On a lower-off/rappel anchor, especially with redundancy these things would be fine.

Though really why skimp? I use 8mm or 10mm CAMP stainless quicklinks, sometimes even as a single point for rappel. No worries on those things.
Rankin

Social climber
Winston-Salem, North Carolina
Nov 4, 2017 - 06:12pm PT
Thanks for posting up Banquo.
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